Method of making a memory plane with powdered keepered material

ABSTRACT

A memory plane includes a keepered word line structure formed by two cooperating molded assemblies, both having recesses for accommodating loose particles of magnetically conductive, but electrically non-conductive material. A contoured word strap assembly is partially disposed in each of said molded assemblies, after which the molded assemblies are joined together whereby the peaks of the contoured word strap assemblies define tunnels in which magnetically coated wires may be inserted, thereby completing the construction of the keepered memory plane.

United States Patent Sinclair [54] METHOD OF MAKING A MEMORY PLANE WITH POWDERED KEEPERED MATERIAL [72] Inventor: William Y. Sinclair, Frenchtown,

[73] Assignee: Thomas & Betts Corporation,

Elizabeth, NJ

[22] Filed: Nov. 16, 1970 [21] Appl. No.: 89,955

[52] US. Cl ..29/604, 340/ 174 PW, 340/174 BC [51] Int. Cl ..H01f 7/06 [58] Field of Search....29/604; 340/174 PW, 174 BC,

3401174 S, 174 MA [56] References Cited UNITED STATES PATENTS 3,604,109 9/1971 Crimmons ..29/604 [451 Oct. 10, 1972 3,465,308 9/1969 Sasaki et al ..340/174 PW Pn'mary Examiner-John F. Campbell Assistant Examiner-Carl E. Hall AttorneyDavid Teschner [57] ABSTRACT 6 Claims, 8 Drawing Figures METHOD OF MAKING A MEMORY PLANEWITI-I POWDERED KEEPERED MATERIAL The present invention relates to a new and-improved keepered memory plane and method of making same wherein the keepered material comprises particles of magnetically conductive, but electrically non-conductive material, which particles are disposed in recesses in a molded assembly or housing. The memory plane also includes the use of a contoured word strap assembly, more particularly a one-sided flat conductor cable which is generally contoured in a sinusoidal configuration whereby when the cable is folded'over itself along its transverse axis the peaks of the word strap assembly are abutting, and the valleys in the cable define generally annular recesses for accommodating the magnetically plated wires.

I-Ieretofore, keepered memory planes have been formed by clading the opposite sides of a complete memory plane with sheets of highly permeable magnetic material. The resulting structure has certain disadvantages, the primary one of which is that the keeper material is only disposed on one side of the word strap and has limited capability in directing and concentrating the magnetic flux generated upon the passage of a pulse through the word strap in the direction of the plated wires.

Another type of memory plane is made using a keepered structure comprising a partially cured mat formed of epoxy and ferrite particles (the latter are magnetically conductive, but electrically non-conductive) and wherein the word straps are forced or embedded into the mat so as to effectively surround each word strap in horseshoe-shaped configuration thereby increasing the flux concentration. However, this technique gives rise to certain disadvantages, the primary one being that of cost and difficulty of manufacture, in addition to the differences in thermal coefficients of expansion between the fully cured mixture of epoxy and ferrite particles and the word straps which may cause mechanical separation of the elements. Accordingly, the lack of dimensional stability of this type of keepered memory plane may cause problems with respect to the efficiency of the plane. Furthermore in that the epoxy defines part of the keeper or flux concentrator, and as such epoxy is not a magnetically conductive material, the presence of the epoxy reduces the efficiency of the ferrite particles in concentrating the magnetic field generated by a word strap upon the passage of current therethrough.

Accordingly, it is an object of this invention to provide a new and improved keepered memory plane and method of making same wherein each word strap is surrounded on three sides with keeper material, and wherein the keeper material is not rigidly bonded to the word straps.

The present invention overcomes the disadvantages of the prior art by providing an assembly wherein the keeper material is accommodated in a recess in a support member, and the word straps are initially configured along with the accompanying carrier material in a generally contoured configuration, and disposed in two of such support members. The word strap is folded over on itself, with the peaks of the word straps abutting so as to define a plurality of generally annular apertures extending orthagonally with respect to the word straps for receiving the magnetically plated wires.

It is readily apparent that as the word strap is a continuous element which is folded upon itself, the upper and lower word straps surrounding the platedwires are effectively connected, thereby providing the turnarounds. The word strap assembly is suitably bonded to eachsupportmember so as to retain the keeper materialand the latter effectively surrounds on three sides in horseshoe-shaped'fashion each. word strap. In that the keeper material, which may be ferriteparticles that are magnetically conductive but electrically non-conductive, are not immersed ina binding material, but rather are maintained in a powderedform, the memory plane is not affected by thermal variations. Furthermore, in that the keeper material consists solely of magnetically conductive but electrically non-conductive particles, the keeper is more-effective in concentrating the magnetic flux as contrasted to theprior art systems wherein thekeeper material includes abinder such as epoxy.

Other and further objects of the invention will be readily apparent from the following description and drawings wherein:

FIG. 1 illustrates a support member for the memory plane of the present invention;

FIG. 2 illustrates a cross section taken along lines 2 2 of FIG. 1;

FIG. 3 illustratesa contoured word strap assembly;

FIG. 4, illustrates a section taken along lines 44 of FIG. 3;

FIG. 5 illustrates the first step in the method of the present invention;

FIG. 6 illustrates the next step in the method of the present invention;

FIG. 7 illustrates the final step in the method of the subject invention; and

FIG. 8 illustrates a cross section taken along lines 8- 8 of FIG. 7. i

Referring to FIGS. 1 and 2, a support member 1 comprises a planar structure preferably made of a dielectric material such as plastic and having formed in one face thereof a generally rectangular recess 2. Disposed in the recess 2 are powdered particles 3 which are magnetically conductive, but non-electrically conductive. For example, the particles 3 may comprise ferrite particles, although other suitable materials may be employed. It is significant to note that the particles are not bound together by an adhesive or binder material, but are in powdered state for relative movement.

A contoured word line structure is illustrated in FIG. 3 as generally comprising a one-sided flat conductor cable 4 including a carrier sheet of insulation 5 onto which is bonded a plurality of generally parallel conductors 6. Conductors 6 may comprise rectangular strips of copper material, and the composite structure 4 is contoured in a generally sinusoidal shape by suitable techniques known to the industry. As illustrated in the cross-section of FIG. 4, the conductors 6 are generally rectangular in cross-section and the plastic carrier sheet 5 extends transversely beyond the outermost conductors.

The first step in the method of making a keepered line, with the word lines disposed downwardly, into the bed of powdered keeper material housed in the recesses in two support members 1. This is illustrated in the exploded view of FIG. 5 wherein two support members l, l are disposed in axial alignment and slightly separated, and the contoured word line assembly is shown with the conductors facing the upwardly disposed recesses of the support members.

FIG. 6 illustrates the next step in the process wherein the elements are joined together so that the conductors 6 are partically embedded in the powdered metal particles 3 of the planar support members.

Turning to FIG. 7, the next step in the process is to fold over the word straps whereby one memory plane is disposed above the other, and the peaks 7 of the composite word strap structure 4 are disposed in abutting relationship. By this arrangement a plurality of generally annular openings 8 running transverse to the longitudinal axis of the cable structure 4 are provided. The support planes are clamped or otherwise bonded together (not shown), with all openings to the recesses being suitably sealed, after which magnetically plated wires 9 are inserted through the openings 8. The combination of the word strap structure and plated wires completes the memory plane.

It is readily apparent that the resulting assembly provides a keepered memory plane wherein each word line 6 is surrounded on all three exposed sides with keepered particles 3 as shown in the cross section of FIG. 8. The outer transverse portions of the carrier strip 5 and the peripheral edges of the support members 2 are suitably sealed to prevent the loss of powdered metal particles 3.

As an alternate process, manufacture wires (which are greater in diameter than the magnetically plated wire) may be employed during the step illustrated in FIG. 7, which manufacture wires would be removed and replaced by magnetically plated wires after the composite structure is fully sealed and clamped together.

It is also readily apparent that two separate assemblies, each comprising a contoured word line structure embedded in a support member may be formed, after which these two assemblies may be joined, followed by insertion of the plated wires to complete the memory plane. The ends of the word lines may then be terminated externally of the support members to complete the turn-arounds.

Another possible method of forming the subject memory plane would be to use a single support member 1 which is made of flexible material, so that it may be folded over itself. As in the previous methods discussed, the one-sided word line cable would be embedded in the ferrite particles, after which the flexible support plane would be folded so as to define the tunnel structures.

It is also readily apparent that each support member 1 may be molded to include contoured side edges corresponding to the contour of the contoured word strap assembly in order to provide increased dimensional stability to the resulting memory plane and to aid in alignment of the various components thereof.

Also, each support member may be formed with a suitable aperture in communication with the inner recess 2. Thus, the entire memory plane may be assembled and sealed prior to introducing the ferrite particles into the recesses 2 via said apertures.

It is also readily apparent that each support member may include sufficient planar surface area to accommodate the various electronic circuitry to be connected to the word straps and magnetically plated wires of the memory plane.

Having thus described the invention, it is not intended that it be so limited, as changes may be made therein without departing from the scope of the invention. Accordingly, it is intended that the foregoing Abstract of the Disclosure and the subject matter described above and shown in the drawings be interpreted as illustrative and not in a limiting sense.

What is claimed is:

1. A method of making a keepered memory plane comprising the steps of:

contouring a word line structure including a plurality of conductors bonded to a sheet of insulating material; embedding the contoured word line structure, with the word lines disposed downwardly, into a bed of powdered keeper material disposed in a recess in a support member to form a composite assembly;

clamping together two of said composite assemblies called for in the preceding step hereof whereby the peaks of the contoured word line structures are in abutting relationship to define a plurality of parallel tunnels extending transversely to the word line structure; and

inserting magnetically plated wires into the tunnels of the preceding step.

2. A method of making a keepered memory plane as set forth in claim 1 with the additional step of interconnecting the word lines of the contoured word line structures to define turnarounds.

3. A method of making a keepered memory plane as in claim 1 with the additional step of sealing the contoured word line structures to the support members to prevent the loss of powdered keeper material from the recesses.

4. A method of making a keepered memory plane comprising the steps of:

contouring a word line structure including a plurality of conductors bonded to a sheet of insulating material; embedding the contoured word line structure, with the exposed word lines disposed downwardly, into two beds of powdered keeper material disposed in recesses respectively in two support members;

folding the word line structure and respective support member to form a stacked arrangement, with the peaks of the contoured word line structures in abutting relationship so as to define a plurality of parallel tunnels extending transversely to the word lines; and

inserting magnetically plated wires into the tunnels of the preceding step.

5. A method of making keepered memory plane as in claim 4 with the additional step of sealing the contoured word line assembly to the support planes, to prevent the loss of powdered keeper material from the recess.

6. A method of making a keepered memory plane as in claim 5 with the additional step of clamping the composite structure together. 

1. A method of making a keepered memory plane comprising the steps of: contouring a word line structure including a plurality of conductors bonded to a sheet of insulating material; embedding the contoured word line structure, with the word lines disposed downwardly, into a bed of powdered keeper material disposed in a recess in a support member to form a composite assembly; clamping together two of said composite assemblies called for in the preceding step hereof whereby the peaks of the contoured word line structures arE in abutting relationship to define a plurality of parallel tunnels extending transversely to the word line structure; and inserting magnetically plated wires into the tunnels of the preceding step.
 2. A method of making a keepered memory plane as set forth in claim 1 with the additional step of interconnecting the word lines of the contoured word line structures to define turnarounds.
 3. A method of making a keepered memory plane as in claim 1 with the additional step of sealing the contoured word line structures to the support members to prevent the loss of powdered keeper material from the recesses.
 4. A method of making a keepered memory plane comprising the steps of: contouring a word line structure including a plurality of conductors bonded to a sheet of insulating material; embedding the contoured word line structure, with the exposed word lines disposed downwardly, into two beds of powdered keeper material disposed in recesses respectively in two support members; folding the word line structure and respective support member to form a stacked arrangement, with the peaks of the contoured word line structures in abutting relationship so as to define a plurality of parallel tunnels extending transversely to the word lines; and inserting magnetically plated wires into the tunnels of the preceding step.
 5. A method of making keepered memory plane as in claim 4 with the additional step of sealing the contoured word line assembly to the support planes, to prevent the loss of powdered keeper material from the recess.
 6. A method of making a keepered memory plane as in claim 5 with the additional step of clamping the composite structure together. 